The term "online films" refers to movies released via the internet which are longer than an hour. These films, compared to ones screened in cinemas, entail lower costs and earn a lot of money from advertisements and pay-per-view services.

As a result of the low costs and good earning potential of these types of films, you now have a lot of low-quality works with vulgar content and shoddy remakes of hit movies entering the market.

However, an online detective film The Guilt recently released on Tencent's video-streaming platform could change people's views about online films.

The suspense story is set on a train where one of the eight passengers is killed on the first night, and then a middle-aged railway policeman tries to find the murderer.

As he hunts for clues in the case, the shocking truth of a carefully-planned revenge emerges.

The three-episode film has an unexpected conclusion that covers school bullying, domestic violence and sexual assault on children.

The Beijing office of Save the Children, an international NGO aimed at protecting children, reviewed the film before the first part was released on May 11.

Wang Xin, the project manager of the charity group says the film focuses on bullying, sexual assault and people's indifference to the victims.

Speaking about the prevalence of sexual violence, Wang says that one in five girls and one in 13 boys around the world have suffered varying degrees of sexual assault.

Last April, Lin Yi-han, a 26-year-old Taiwan writer committed suicide at her apartment in Taipei, shortly after the publication of her novel Fang Si-Qi's First Love Paradise that tells the story of a teenage girl being sexually assaulted by her teacher.

The story, which was said to be based on Lin's own life experience, left her physically and mentally scarred for years.

The Guilt focuses on sexual violence and other social issues, according to its sponsor Tencent Penguin Pictures.

The film scored 7.5 out of 10 on Douban, a popular Chinese film rating site, by Monday, three days after its debut.

Commenting on the film, one netizen says on Douban: "Though the setting of The Guilt is similar to the movie Murder on the Orient Express (2017), the theme, storyline and actors' performance are still outstanding when it comes to online films."

Chang Bin, vice-president of Tencent Penguin Pictures, says: "In the past, online films prioritized entertaining audiences over tackling social problems. But I think they are changing."